Water pump failure usually occurs as a result of leakage of a shaft seal. When such leakage develops, the typical solution is to replace the entire water pump.
However, when the water pump is combined with the power steering pump of a motor vehicle, replacement of the combined unit becomes prohibitively expensive. What is needed is a seal assembly which can be easily serviced and replaced without requiring the entire water pump and power steering pump assembly to be replaced.
In accordance with the present invention, a water pump has an impeller removably secured to the outer end of a shaft. A seal in the water pump housing surrounds the shaft. The seal is axially removable over the outer end of the shaft after the impeller is removed.
Preferably the seal is pressed into an annular adapter in the housing. A bushing between the seal and the impeller is compressed by axial movement of the impeller as it is attached to the end of the shaft. Specifically, the fastener attaching the impeller to the shaft exerts an axial force against the impeller and then against the seal. This presses the seal more firmly into the adapter. The bushing, moreover, serves as a protective sleeve to prevent corrosion of the shaft surface. Shaft surface corrosion is undesirable because it may prevent the replacement seal from forming a water-tight seal around the shaft.
The seal arrangement of this invention is preferably employed in an in-line water pump and power steering pump assembly wherein the shaft which pumps power steering fluid is the same shaft to which the water pump impeller is secured.
One object of this invention is to provide a shaft seal for a water pump and power steering pump assembly having the foregoing features and capabilities.
Another object is to provide a shaft seal for a water pump and power steering pump assembly which is composed of a relatively few simple parts, is capable of being readily replaced without requiring replacement of the entire pump assembly, and which is relatively inexpensive to manufacture and assemble.
These and other objects, features and advantages of the invention will become more apparent as the following description proceeds, especially when considered with the accompanying drawings.